BA has occasionally popped up on cashback sites, but it's usually a very poor rate. IIRC, last time it was a fixed rate of < £1 for shorthaul and ~ £4 for long haul (or something like that). Hilton cashback is a lottery. First if you have any status with them it's a poor 1% and then all kinds of reasons for declining. Most notable are booking a Hilton Honors rate, or receiving an upgrade. Instead of the 1% cashback, I usually book through Avios eStore which is as much a lottery but a better return of 6-8 Avios/£ if it comes through.